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class Solution {
public:
    vector<vector<int>> ans;
    vector<int> path;
    vector<bool> st;

    vector<vector<int>> permute(vector<int>& nums) {
        path.resize(nums.size(), 0);
        st.resize(nums.size(), false);
        dfs(nums, 0);
        return ans;
    }

    void dfs(vector<int>& nums, int u){
        if(u == nums.size()){
            ans.push_back(path);
            return;
        }

        for(int i = 0; i < nums.size(); i ++){
            if(!st[i]){
                path[u] = nums[i];
                st[i] = true;
                dfs(nums, u + 1);
                st[i] = false;
            }
        }
    }

};